gnulib/import/m4/std-gnu11.m4

   1 # Prefer GNU C11 and C++11 to earlier versions.  -*- coding: utf-8 -*-
   2
   3 # This implementation is taken from GNU Autoconf lib/autoconf/c.m4
   4 # commit 017d5ddd82854911f0119691d91ea8a1438824d6
   5 # dated Sun Apr 3 13:57:17 2016 -0700
   6 # This implementation will be obsolete once we can assume Autoconf 2.70
   7 # or later is installed everywhere a Gnulib program might be developed.
   8
   9
  10 # Copyright (C) 2001-2019 Free Software Foundation, Inc.
  11
  12 # This program is free software; you can redistribute it and/or modify
  13 # it under the terms of the GNU General Public License as published by
  14 # the Free Software Foundation, either version 3 of the License, or
  15 # (at your option) any later version.
  16 #
  17 # This program is distributed in the hope that it will be useful,
  18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 # GNU General Public License for more details.
  21 #
  22 # You should have received a copy of the GNU General Public License
  23 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
  24
  25 # Written by David MacKenzie, with help from
  26 # Akim Demaille, Paul Eggert,
  27 # François Pinard, Karl Berry, Richard Pixley, Ian Lance Taylor,
  28 # Roland McGrath, Noah Friedman, david d zuhn, and many others.
  29
  30
  31 # AC_PROG_CC([COMPILER ...])
  32 # --------------------------
  33 # COMPILER ... is a space separated list of C compilers to search for.
  34 # This just gives the user an opportunity to specify an alternative
  35 # search list for the C compiler.
  36 AC_DEFUN_ONCE([AC_PROG_CC],
  37 [AC_LANG_PUSH(C)dnl
  38 AC_ARG_VAR([CC],     [C compiler command])dnl
  39 AC_ARG_VAR([CFLAGS], [C compiler flags])dnl
  40 _AC_ARG_VAR_LDFLAGS()dnl
  41 _AC_ARG_VAR_LIBS()dnl
  42 _AC_ARG_VAR_CPPFLAGS()dnl
  43 m4_ifval([$1],
  44       [AC_CHECK_TOOLS(CC, [$1])],
  45 [AC_CHECK_TOOL(CC, gcc)
  46 if test -z "$CC"; then
  47   dnl Here we want:
  48   dnl   AC_CHECK_TOOL(CC, cc)
  49   dnl but without the check for a tool without the prefix.
  50   dnl Until the check is removed from there, copy the code:
  51   if test -n "$ac_tool_prefix"; then
  52     AC_CHECK_PROG(CC, [${ac_tool_prefix}cc], [${ac_tool_prefix}cc])
  53   fi
  54 fi
  55 if test -z "$CC"; then
  56   AC_CHECK_PROG(CC, cc, cc, , , /usr/ucb/cc)
  57 fi
  58 if test -z "$CC"; then
  59   AC_CHECK_TOOLS(CC, cl.exe)
  60 fi
  61 if test -z "$CC"; then
  62   AC_CHECK_TOOL(CC, clang)
  63 fi
  64 ])
  65
  66 test -z "$CC" && AC_MSG_FAILURE([no acceptable C compiler found in \$PATH])
  67
  68 # Provide some information about the compiler.
  69 _AS_ECHO_LOG([checking for _AC_LANG compiler version])
  70 set X $ac_compile
  71 ac_compiler=$[2]
  72 for ac_option in --version -v -V -qversion -version; do
  73   m4_ifdef([_AC_DO_LIMIT],[_AC_DO_LIMIT],[_AC_DO])([$ac_compiler $ac_option >&AS_MESSAGE_LOG_FD])
  74 done
  75
  76 m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
  77 m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
  78 _AC_LANG_COMPILER_GNU
  79 if test $ac_compiler_gnu = yes; then
  80   GCC=yes
  81 else
  82   GCC=
  83 fi
  84 _AC_PROG_CC_G
  85 dnl
  86 dnl Set ac_prog_cc_stdc to the supported C version.
  87 dnl Also set the documented variable ac_cv_prog_cc_stdc;
  88 dnl its name was chosen when it was cached, but it is no longer cached.
  89 _AC_PROG_CC_C11([ac_prog_cc_stdc=c11
  90                  ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c11],
  91   [_AC_PROG_CC_C99([ac_prog_cc_stdc=c99
  92                     ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c99],
  93      [_AC_PROG_CC_C89([ac_prog_cc_stdc=c89
  94                        ac_cv_prog_cc_stdc=$ac_cv_prog_cc_c89],
  95                       [ac_prog_cc_stdc=no
  96                        ac_cv_prog_cc_stdc=no])])])
  97 dnl
  98 AC_LANG_POP(C)dnl
  99 ])# AC_PROG_CC
 100
 101
 102
 103 # AC_PROG_CXX([LIST-OF-COMPILERS])
 104 # --------------------------------
 105 # LIST-OF-COMPILERS is a space separated list of C++ compilers to search
 106 # for (if not specified, a default list is used).  This just gives the
 107 # user an opportunity to specify an alternative search list for the C++
 108 # compiler.
 109 # aCC   HP-UX C++ compiler much better than `CC', so test before.
 110 # FCC   Fujitsu C++ compiler
 111 # KCC   KAI C++ compiler
 112 # RCC   Rational C++
 113 # xlC_r AIX C Set++ (with support for reentrant code)
 114 # xlC   AIX C Set++
 115 AC_DEFUN([AC_PROG_CXX],
 116 [AC_LANG_PUSH(C++)dnl
 117 AC_ARG_VAR([CXX],      [C++ compiler command])dnl
 118 AC_ARG_VAR([CXXFLAGS], [C++ compiler flags])dnl
 119 _AC_ARG_VAR_LDFLAGS()dnl
 120 _AC_ARG_VAR_LIBS()dnl
 121 _AC_ARG_VAR_CPPFLAGS()dnl
 122 _AC_ARG_VAR_PRECIOUS([CCC])dnl
 123 if test -z "$CXX"; then
 124   if test -n "$CCC"; then
 125     CXX=$CCC
 126   else
 127     AC_CHECK_TOOLS(CXX,
 128                    [m4_default([$1],
 129                                [g++ c++ gpp aCC CC cxx cc++ cl.exe FCC KCC RCC xlC_r xlC clang++])],
 130                    g++)
 131   fi
 132 fi
 133 # Provide some information about the compiler.
 134 _AS_ECHO_LOG([checking for _AC_LANG compiler version])
 135 set X $ac_compile
 136 ac_compiler=$[2]
 137 for ac_option in --version -v -V -qversion; do
 138   m4_ifdef([_AC_DO_LIMIT],[_AC_DO_LIMIT],[_AC_DO])([$ac_compiler $ac_option >&AS_MESSAGE_LOG_FD])
 139 done
 140
 141 m4_expand_once([_AC_COMPILER_EXEEXT])[]dnl
 142 m4_expand_once([_AC_COMPILER_OBJEXT])[]dnl
 143 _AC_LANG_COMPILER_GNU
 144 if test $ac_compiler_gnu = yes; then
 145   GXX=yes
 146 else
 147   GXX=
 148 fi
 149 _AC_PROG_CXX_G
 150 _AC_PROG_CXX_CXX11([ac_prog_cxx_stdcxx=cxx11
 151                     ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx11
 152                     ac_cv_prog_cxx_cxx98=$ac_cv_prog_cxx_cxx11],
 153    [_AC_PROG_CXX_CXX98([ac_prog_cxx_stdcxx=cxx98
 154                         ac_cv_prog_cxx_stdcxx=$ac_cv_prog_cxx_cxx98],
 155                        [ac_prog_cxx_stdcxx=no
 156                         ac_cv_prog_cxx_stdcxx=no])])
 157 AC_LANG_POP(C++)dnl
 158 ])# AC_PROG_CXX
 159
 160
 161 # _AC_C_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
 162 #               ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
 163 # --------------------------------------------------------------
 164 # Check whether the C compiler accepts features of STANDARD (e.g `c89', `c99')
 165 # by trying to compile a program of TEST-PROLOGUE and TEST-BODY.  If this fails,
 166 # try again with each compiler option in the space-separated OPTION-LIST; if one
 167 # helps, append it to CC.  If eventually successful, run ACTION-IF-AVAILABLE,
 168 # else ACTION-IF-UNAVAILABLE.
 169 AC_DEFUN([_AC_C_STD_TRY],
 170 [AC_MSG_CHECKING([for $CC option to enable ]m4_translit($1, [c], [C])[ features])
 171 AC_CACHE_VAL(ac_cv_prog_cc_$1,
 172 [ac_cv_prog_cc_$1=no
 173 ac_save_CC=$CC
 174 AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
 175 for ac_arg in '' $4
 176 do
 177   CC="$ac_save_CC $ac_arg"
 178   _AC_COMPILE_IFELSE([], [ac_cv_prog_cc_$1=$ac_arg])
 179   test "x$ac_cv_prog_cc_$1" != "xno" && break
 180 done
 181 rm -f conftest.$ac_ext
 182 CC=$ac_save_CC
 183 ])# AC_CACHE_VAL
 184 ac_prog_cc_stdc_options=
 185 case "x$ac_cv_prog_cc_$1" in
 186   x)
 187     AC_MSG_RESULT([none needed]) ;;
 188   xno)
 189     AC_MSG_RESULT([unsupported]) ;;
 190   *)
 191     ac_prog_cc_stdc_options=" $ac_cv_prog_cc_$1"
 192     CC=$CC$ac_prog_cc_stdc_options
 193     AC_MSG_RESULT([$ac_cv_prog_cc_$1]) ;;
 194 esac
 195 AS_IF([test "x$ac_cv_prog_cc_$1" != xno], [$5], [$6])
 196 ])# _AC_C_STD_TRY
 197
 198 # _AC_C_C99_TEST_HEADER
 199 # ---------------------
 200 # A C header suitable for testing for C99.
 201 AC_DEFUN([_AC_C_C99_TEST_HEADER],
 202 [[#include <stdarg.h>
 203 #include <stdbool.h>
 204 #include <stddef.h>
 205 #include <stdlib.h>
 206 #include <wchar.h>
 207 #include <stdio.h>
 208
 209 // Check varargs macros.  These examples are taken from C99 6.10.3.5.
 210 #define debug(...) fprintf (stderr, __VA_ARGS__)
 211 #define showlist(...) puts (#__VA_ARGS__)
 212 #define report(test,...) ((test) ? puts (#test) : printf (__VA_ARGS__))
 213 static void
 214 test_varargs_macros (void)
 215 {
 216   int x = 1234;
 217   int y = 5678;
 218   debug ("Flag");
 219   debug ("X = %d\n", x);
 220   showlist (The first, second, and third items.);
 221   report (x>y, "x is %d but y is %d", x, y);
 222 }
 223
 224 // Check long long types.
 225 #define BIG64 18446744073709551615ull
 226 #define BIG32 4294967295ul
 227 #define BIG_OK (BIG64 / BIG32 == 4294967297ull && BIG64 % BIG32 == 0)
 228 #if !BIG_OK
 229   your preprocessor is broken;
 230 #endif
 231 #if BIG_OK
 232 #else
 233   your preprocessor is broken;
 234 #endif
 235 static long long int bignum = -9223372036854775807LL;
 236 static unsigned long long int ubignum = BIG64;
 237
 238 struct incomplete_array
 239 {
 240   int datasize;
 241   double data[];
 242 };
 243
 244 struct named_init {
 245   int number;
 246   const wchar_t *name;
 247   double average;
 248 };
 249
 250 typedef const char *ccp;
 251
 252 static inline int
 253 test_restrict (ccp restrict text)
 254 {
 255   // See if C++-style comments work.
 256   // Iterate through items via the restricted pointer.
 257   // Also check for declarations in for loops.
 258   for (unsigned int i = 0; *(text+i) != '\0'; ++i)
 259     continue;
 260   return 0;
 261 }
 262
 263 // Check varargs and va_copy.
 264 static bool
 265 test_varargs (const char *format, ...)
 266 {
 267   va_list args;
 268   va_start (args, format);
 269   va_list args_copy;
 270   va_copy (args_copy, args);
 271
 272   const char *str = "";
 273   int number = 0;
 274   float fnumber = 0;
 275
 276   while (*format)
 277     {
 278       switch (*format++)
 279         {
 280         case 's': // string
 281           str = va_arg (args_copy, const char *);
 282           break;
 283         case 'd': // int
 284           number = va_arg (args_copy, int);
 285           break;
 286         case 'f': // float
 287           fnumber = va_arg (args_copy, double);
 288           break;
 289         default:
 290           break;
 291         }
 292     }
 293   va_end (args_copy);
 294   va_end (args);
 295
 296   return *str && number && fnumber;
 297 }]])# _AC_C_C99_TEST_HEADER
 298
 299 # _AC_C_C99_TEST_BODY
 300 # -------------------
 301 # A C body suitable for testing for C99, assuming the corresponding header.
 302 AC_DEFUN([_AC_C_C99_TEST_BODY],
 303 [[
 304   // Check bool.
 305   _Bool success = false;
 306
 307   // Check restrict.
 308   if (test_restrict ("String literal") == 0)
 309     success = true;
 310   char *restrict newvar = "Another string";
 311
 312   // Check varargs.
 313   success &= test_varargs ("s, d' f .", "string", 65, 34.234);
 314   test_varargs_macros ();
 315
 316   // Check flexible array members.
 317   struct incomplete_array *ia =
 318     malloc (sizeof (struct incomplete_array) + (sizeof (double) * 10));
 319   ia->datasize = 10;
 320   for (int i = 0; i < ia->datasize; ++i)
 321     ia->data[i] = i * 1.234;
 322
 323   // Check named initializers.
 324   struct named_init ni = {
 325     .number = 34,
 326     .name = L"Test wide string",
 327     .average = 543.34343,
 328   };
 329
 330   ni.number = 58;
 331
 332   int dynamic_array[ni.number];
 333   dynamic_array[ni.number - 1] = 543;
 334
 335   // work around unused variable warnings
 336   return (!success || bignum == 0LL || ubignum == 0uLL || newvar[0] == 'x'
 337           || dynamic_array[ni.number - 1] != 543);
 338 ]])
 339
 340 # _AC_PROG_CC_C99 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
 341 # ----------------------------------------------------------------
 342 # If the C compiler is not in ISO C99 mode by default, try to add an
 343 # option to output variable CC to make it so.  This macro tries
 344 # various options that select ISO C99 on some system or another.  It
 345 # considers the compiler to be in ISO C99 mode if it handles _Bool,
 346 # // comments, flexible array members, inline, long long int, mixed
 347 # code and declarations, named initialization of structs, restrict,
 348 # va_copy, varargs macros, variable declarations in for loops and
 349 # variable length arrays.
 350 AC_DEFUN([_AC_PROG_CC_C99],
 351 [_AC_C_STD_TRY([c99],
 352 [_AC_C_C99_TEST_HEADER],
 353 [_AC_C_C99_TEST_BODY],
 354 dnl Try
 355 dnl GCC         -std=gnu99 (unused restrictive modes: -std=c99 -std=iso9899:1999)
 356 dnl IBM XL C    -qlanglvl=extc1x (V12.1; does not pass C11 test)
 357 dnl IBM XL C    -qlanglvl=extc99
 358 dnl             (pre-V12.1; unused restrictive mode: -qlanglvl=stdc99)
 359 dnl HP cc       -AC99
 360 dnl Intel ICC   -std=c99, -c99 (deprecated)
 361 dnl IRIX        -c99
 362 dnl Solaris     -D_STDC_C99=
 363 dnl             cc's -xc99 option uses linker magic to define the external
 364 dnl             symbol __xpg4 as if by "int __xpg4 = 1;", which enables C99
 365 dnl             behavior for C library functions.  This is not wanted here,
 366 dnl             because it means that a single module compiled with -xc99
 367 dnl             alters C runtime behavior for the entire program, not for
 368 dnl             just the module.  Instead, define the (private) symbol
 369 dnl             _STDC_C99, which suppresses a bogus failure in <stdbool.h>.
 370 dnl             The resulting compiler passes the test case here, and that's
 371 dnl             good enough.  For more, please see the thread starting at:
 372 dnl            https://lists.gnu.org/r/autoconf/2010-12/msg00059.html
 373 dnl Tru64       -c99
 374 dnl with extended modes being tried first.
 375 [[-std=gnu99 -std=c99 -c99 -AC99 -D_STDC_C99= -qlanglvl=extc1x -qlanglvl=extc99]], [$1], [$2])[]dnl
 376 ])# _AC_PROG_CC_C99
 377
 378
 379 # _AC_PROG_CC_C11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
 380 # ----------------------------------------------------------------
 381 # If the C compiler is not in ISO C11 mode by default, try to add an
 382 # option to output variable CC to make it so.  This macro tries
 383 # various options that select ISO C11 on some system or another.  It
 384 # considers the compiler to be in ISO C11 mode if it handles _Alignas,
 385 # _Alignof, _Noreturn, _Static_assert, UTF-8 string literals,
 386 # duplicate typedefs, and anonymous structures and unions.
 387 AC_DEFUN([_AC_PROG_CC_C11],
 388 [_AC_C_STD_TRY([c11],
 389 [_AC_C_C99_TEST_HEADER[
 390 // Check _Alignas.
 391 char _Alignas (double) aligned_as_double;
 392 char _Alignas (0) no_special_alignment;
 393 extern char aligned_as_int;
 394 char _Alignas (0) _Alignas (int) aligned_as_int;
 395
 396 // Check _Alignof.
 397 enum
 398 {
 399   int_alignment = _Alignof (int),
 400   int_array_alignment = _Alignof (int[100]),
 401   char_alignment = _Alignof (char)
 402 };
 403 _Static_assert (0 < -_Alignof (int), "_Alignof is signed");
 404
 405 // Check _Noreturn.
 406 int _Noreturn does_not_return (void) { for (;;) continue; }
 407
 408 // Check _Static_assert.
 409 struct test_static_assert
 410 {
 411   int x;
 412   _Static_assert (sizeof (int) <= sizeof (long int),
 413                   "_Static_assert does not work in struct");
 414   long int y;
 415 };
 416
 417 // Check UTF-8 literals.
 418 #define u8 syntax error!
 419 char const utf8_literal[] = u8"happens to be ASCII" "another string";
 420
 421 // Check duplicate typedefs.
 422 typedef long *long_ptr;
 423 typedef long int *long_ptr;
 424 typedef long_ptr long_ptr;
 425
 426 // Anonymous structures and unions -- taken from C11 6.7.2.1 Example 1.
 427 struct anonymous
 428 {
 429   union {
 430     struct { int i; int j; };
 431     struct { int k; long int l; } w;
 432   };
 433   int m;
 434 } v1;
 435 ]],
 436 [_AC_C_C99_TEST_BODY[
 437   v1.i = 2;
 438   v1.w.k = 5;
 439   _Static_assert ((offsetof (struct anonymous, i)
 440                    == offsetof (struct anonymous, w.k)),
 441                   "Anonymous union alignment botch");
 442 ]],
 443 dnl Try
 444 dnl GCC         -std=gnu11 (unused restrictive mode: -std=c11)
 445 dnl with extended modes being tried first.
 446 dnl
 447 dnl Do not try -qlanglvl=extc1x, because IBM XL C V12.1 (the latest version as
 448 dnl of September 2012) does not pass the C11 test.  For now, try extc1x when
 449 dnl compiling the C99 test instead, since it enables _Static_assert and
 450 dnl _Noreturn, which is a win.  If -qlanglvl=extc11 or -qlanglvl=extc1x passes
 451 dnl the C11 test in some future version of IBM XL C, we'll add it here,
 452 dnl preferably extc11.
 453 [[-std=gnu11]], [$1], [$2])[]dnl
 454 ])# _AC_PROG_CC_C11
 455
 456
 457 # AC_PROG_CC_C89
 458 # --------------
 459 # Do not use AU_ALIAS here and in AC_PROG_CC_C99 and AC_PROG_CC_STDC,
 460 # as that'd be incompatible with how Automake redefines AC_PROG_CC.  See
 461 # <https://lists.gnu.org/r/autoconf/2012-10/msg00048.html>.
 462 AU_DEFUN([AC_PROG_CC_C89],
 463   [AC_REQUIRE([AC_PROG_CC])],
 464   [$0 is obsolete; use AC_PROG_CC]
 465 )
 466
 467 # AC_PROG_CC_C99
 468 # --------------
 469 AU_DEFUN([AC_PROG_CC_C99],
 470   [AC_REQUIRE([AC_PROG_CC])],
 471   [$0 is obsolete; use AC_PROG_CC]
 472 )
 473
 474 # AC_PROG_CC_STDC
 475 # ---------------
 476 AU_DEFUN([AC_PROG_CC_STDC],
 477   [AC_REQUIRE([AC_PROG_CC])],
 478   [$0 is obsolete; use AC_PROG_CC]
 479 )
 480
 481
 482 # AC_C_PROTOTYPES
 483 # ---------------
 484 # Check if the C compiler supports prototypes, included if it needs
 485 # options.
 486 AC_DEFUN([AC_C_PROTOTYPES],
 487 [AC_REQUIRE([AC_PROG_CC])dnl
 488 if test "$ac_prog_cc_stdc" != no; then
 489   AC_DEFINE(PROTOTYPES, 1,
 490             [Define to 1 if the C compiler supports function prototypes.])
 491   AC_DEFINE(__PROTOTYPES, 1,
 492             [Define like PROTOTYPES; this can be used by system headers.])
 493 fi
 494 ])# AC_C_PROTOTYPES
 495
 496
 497 # _AC_CXX_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
 498 #                 ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
 499 # ----------------------------------------------------------------
 500 # Check whether the C++ compiler accepts features of STANDARD (e.g
 501 # `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
 502 # and TEST-BODY.  If this fails, try again with each compiler option
 503 # in the space-separated OPTION-LIST; if one helps, append it to CXX.
 504 # If eventually successful, run ACTION-IF-AVAILABLE, else
 505 # ACTION-IF-UNAVAILABLE.
 506 AC_DEFUN([_AC_CXX_STD_TRY],
 507 [AC_MSG_CHECKING([for $CXX option to enable ]m4_translit(m4_translit($1, [x], [+]), [a-z], [A-Z])[ features])
 508 AC_LANG_PUSH(C++)dnl
 509 AC_CACHE_VAL(ac_cv_prog_cxx_$1,
 510 [ac_cv_prog_cxx_$1=no
 511 ac_save_CXX=$CXX
 512 AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
 513 for ac_arg in '' $4
 514 do
 515   CXX="$ac_save_CXX $ac_arg"
 516   _AC_COMPILE_IFELSE([], [ac_cv_prog_cxx_$1=$ac_arg])
 517   test "x$ac_cv_prog_cxx_$1" != "xno" && break
 518 done
 519 rm -f conftest.$ac_ext
 520 CXX=$ac_save_CXX
 521 ])# AC_CACHE_VAL
 522 ac_prog_cxx_stdcxx_options=
 523 case "x$ac_cv_prog_cxx_$1" in
 524   x)
 525     AC_MSG_RESULT([none needed]) ;;
 526   xno)
 527     AC_MSG_RESULT([unsupported]) ;;
 528   *)
 529     ac_prog_cxx_stdcxx_options=" $ac_cv_prog_cxx_$1"
 530     CXX=$CXX$ac_prog_cxx_stdcxx_options
 531     AC_MSG_RESULT([$ac_cv_prog_cxx_$1]) ;;
 532 esac
 533 AC_LANG_POP(C++)dnl
 534 AS_IF([test "x$ac_cv_prog_cxx_$1" != xno], [$5], [$6])
 535 ])# _AC_CXX_STD_TRY
 536
 537 # _AC_CXX_CXX98_TEST_HEADER
 538 # -------------------------
 539 # A C++ header suitable for testing for CXX98.
 540 AC_DEFUN([_AC_CXX_CXX98_TEST_HEADER],
 541 [[
 542 #include <algorithm>
 543 #include <cstdlib>
 544 #include <fstream>
 545 #include <iomanip>
 546 #include <iostream>
 547 #include <list>
 548 #include <map>
 549 #include <set>
 550 #include <sstream>
 551 #include <stdexcept>
 552 #include <string>
 553 #include <utility>
 554 #include <vector>
 555
 556 namespace test {
 557   typedef std::vector<std::string> string_vec;
 558   typedef std::pair<int,bool> map_value;
 559   typedef std::map<std::string,map_value> map_type;
 560   typedef std::set<int> set_type;
 561
 562   template<typename T>
 563   class printer {
 564   public:
 565     printer(std::ostringstream& os): os(os) {}
 566     void operator() (T elem) { os << elem << std::endl; }
 567   private:
 568     std::ostringstream& os;
 569   };
 570 }
 571 ]])# _AC_CXX_CXX98_TEST_HEADER
 572
 573 # _AC_CXX_CXX98_TEST_BODY
 574 # -----------------------
 575 # A C++ body suitable for testing for CXX98, assuming the corresponding header.
 576 AC_DEFUN([_AC_CXX_CXX98_TEST_BODY],
 577 [[
 578
 579 try {
 580   // Basic string.
 581   std::string teststr("ASCII text");
 582   teststr += " string";
 583
 584   // Simple vector.
 585   test::string_vec testvec;
 586   testvec.push_back(teststr);
 587   testvec.push_back("foo");
 588   testvec.push_back("bar");
 589   if (testvec.size() != 3) {
 590     throw std::runtime_error("vector size is not 1");
 591   }
 592
 593   // Dump vector into stringstream and obtain string.
 594   std::ostringstream os;
 595   for (test::string_vec::const_iterator i = testvec.begin();
 596        i != testvec.end(); ++i) {
 597     if (i + 1 != testvec.end()) {
 598       os << teststr << '\n';
 599     }
 600   }
 601   // Check algorithms work.
 602   std::for_each(testvec.begin(), testvec.end(), test::printer<std::string>(os));
 603   std::string os_out = os.str();
 604
 605   // Test pair and map.
 606   test::map_type testmap;
 607   testmap.insert(std::make_pair(std::string("key"),
 608                                 std::make_pair(53,false)));
 609
 610   // Test set.
 611   int values[] = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
 612   test::set_type testset(values, values + sizeof(values)/sizeof(values[0]));
 613   std::list<int> testlist(testset.begin(), testset.end());
 614   std::copy(testset.begin(), testset.end(), std::back_inserter(testlist));
 615 } catch (const std::exception& e) {
 616   std::cerr << "Caught exception: " << e.what() << std::endl;
 617
 618   // Test fstream
 619   std::ofstream of("test.txt");
 620   of << "Test ASCII text\n" << std::flush;
 621   of << "N= " << std::hex << std::setw(8) << std::left << 534 << std::endl;
 622   of.close();
 623 }
 624 std::exit(0);
 625 ]])
 626
 627 # _AC_CXX_CXX11_TEST_HEADER
 628 # -------------------------
 629 # A C++ header suitable for testing for CXX11.
 630 AC_DEFUN([_AC_CXX_CXX11_TEST_HEADER],
 631 [[
 632 #include <deque>
 633 #include <functional>
 634 #include <memory>
 635 #include <tuple>
 636 #include <array>
 637 #include <regex>
 638 #include <iostream>
 639
 640 namespace cxx11test
 641 {
 642   typedef std::shared_ptr<std::string> sptr;
 643   typedef std::weak_ptr<std::string> wptr;
 644
 645   typedef std::tuple<std::string,int,double> tp;
 646   typedef std::array<int, 20> int_array;
 647
 648   constexpr int get_val() { return 20; }
 649
 650   struct testinit
 651   {
 652     int i;
 653     double d;
 654   };
 655
 656   class delegate  {
 657   public:
 658     delegate(int n) : n(n) {}
 659     delegate(): delegate(2354) {}
 660
 661     virtual int getval() { return this->n; };
 662   protected:
 663     int n;
 664   };
 665
 666   class overridden : public delegate {
 667   public:
 668     overridden(int n): delegate(n) {}
 669     virtual int getval() override final { return this->n * 2; }
 670   };
 671
 672   class nocopy {
 673   public:
 674     nocopy(int i): i(i) {}
 675     nocopy() = default;
 676     nocopy(const nocopy&) = delete;
 677     nocopy & operator=(const nocopy&) = delete;
 678   private:
 679     int i;
 680   };
 681 }
 682 ]])# _AC_CXX_CXX11_TEST_HEADER
 683
 684 # _AC_CXX_CXX11_TEST_BODY
 685 # -----------------------
 686 # A C++ body suitable for testing for CXX11, assuming the corresponding header.
 687 AC_DEFUN([_AC_CXX_CXX11_TEST_BODY],
 688 [[
 689 {
 690   // Test auto and decltype
 691   std::deque<int> d;
 692   d.push_front(43);
 693   d.push_front(484);
 694   d.push_front(3);
 695   d.push_front(844);
 696   int total = 0;
 697   for (auto i = d.begin(); i != d.end(); ++i) { total += *i; }
 698
 699   auto a1 = 6538;
 700   auto a2 = 48573953.4;
 701   auto a3 = "String literal";
 702
 703   decltype(a2) a4 = 34895.034;
 704 }
 705 {
 706   // Test constexpr
 707   short sa[cxx11test::get_val()] = { 0 };
 708 }
 709 {
 710   // Test initializer lists
 711   cxx11test::testinit il = { 4323, 435234.23544 };
 712 }
 713 {
 714   // Test range-based for and lambda
 715   cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
 716   for (int &x : array) { x += 23; }
 717   std::for_each(array.begin(), array.end(), [](int v1){ std::cout << v1; });
 718 }
 719 {
 720   using cxx11test::sptr;
 721   using cxx11test::wptr;
 722
 723   sptr sp(new std::string("ASCII string"));
 724   wptr wp(sp);
 725   sptr sp2(wp);
 726 }
 727 {
 728   cxx11test::tp tuple("test", 54, 45.53434);
 729   double d = std::get<2>(tuple);
 730   std::string s;
 731   int i;
 732   std::tie(s,i,d) = tuple;
 733 }
 734 {
 735   static std::regex filename_regex("^_?([a-z0-9_.]+-)+[a-z0-9]+$");
 736   std::string testmatch("Test if this string matches");
 737   bool match = std::regex_search(testmatch, filename_regex);
 738 }
 739 {
 740   cxx11test::int_array array = {9, 7, 13, 15, 4, 18, 12, 10, 5, 3, 14, 19, 17, 8, 6, 20, 16, 2, 11, 1};
 741   cxx11test::int_array::size_type size = array.size();
 742 }
 743 {
 744   // Test constructor delegation
 745   cxx11test::delegate d1;
 746   cxx11test::delegate d2();
 747   cxx11test::delegate d3(45);
 748 }
 749 {
 750   // Test override and final
 751   cxx11test::overridden o1(55464);
 752 }
 753 {
 754   // Test nullptr
 755   char *c = nullptr;
 756 }
 757 {
 758   // Test template brackets
 759   std::vector<std::pair<int,char*>> v1;
 760 }
 761 {
 762   // Unicode literals
 763   char const *utf8 = u8"UTF-8 string \u2500";
 764   char16_t const *utf16 = u"UTF-8 string \u2500";
 765   char32_t const *utf32 = U"UTF-32 string \u2500";
 766 }
 767 ]])
 768
 769 # _AC_PROG_CXX_CXX98 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
 770 # -------------------------------------------------------------------
 771
 772 # If the C++ compiler is not in ISO C++98 mode by default, try to add
 773 # an option to output variable CXX to make it so.  This macro tries
 774 # various options that select ISO C++98 on some system or another.  It
 775 # considers the compiler to be in ISO C++98 mode if it handles basic
 776 # features of the std namespace including: string, containers (list,
 777 # map, set, vector), streams (fstreams, iostreams, stringstreams,
 778 # iomanip), pair, exceptions and algorithms.
 779
 780
 781 AC_DEFUN([_AC_PROG_CXX_CXX98],
 782 [_AC_CXX_STD_TRY([cxx98],
 783 [_AC_CXX_CXX98_TEST_HEADER],
 784 [_AC_CXX_CXX98_TEST_BODY],
 785 dnl Try
 786 dnl GCC         -std=gnu++98 (unused restrictive mode: -std=c++98)
 787 dnl IBM XL C    -qlanglvl=extended
 788 dnl HP aC++     -AA
 789 dnl Intel ICC   -std=gnu++98
 790 dnl Solaris     N/A (default)
 791 dnl Tru64       N/A (default, but -std gnu could be used)
 792 dnl with extended modes being tried first.
 793 [[-std=gnu++98 -std=c++98 -qlanglvl=extended -AA]], [$1], [$2])[]dnl
 794 ])# _AC_PROG_CXX_CXX98
 795
 796 # _AC_PROG_CXX_CXX11 ([ACTION-IF-AVAILABLE], [ACTION-IF-UNAVAILABLE])
 797 # -------------------------------------------------------------------
 798 # If the C++ compiler is not in ISO CXX11 mode by default, try to add
 799 # an option to output variable CXX to make it so.  This macro tries
 800 # various options that select ISO C++11 on some system or another.  It
 801 # considers the compiler to be in ISO C++11 mode if it handles all the
 802 # tests from the C++98 checks, plus the following: Language features
 803 # (auto, constexpr, decltype, default/deleted constructors, delegate
 804 # constructors, final, initializer lists, lambda functions, nullptr,
 805 # override, range-based for loops, template brackets without spaces,
 806 # unicode literals) and library features (array, memory (shared_ptr,
 807 # weak_ptr), regex and tuple types).
 808 AC_DEFUN([_AC_PROG_CXX_CXX11],
 809 [_AC_CXX_STD_TRY([cxx11],
 810 [_AC_CXX_CXX11_TEST_HEADER
 811 _AC_CXX_CXX98_TEST_HEADER],
 812 [_AC_CXX_CXX11_TEST_BODY
 813 _AC_CXX_CXX98_TEST_BODY],
 814 dnl Try
 815 dnl GCC         -std=gnu++11 (unused restrictive mode: -std=c++11) [and 0x variants]
 816 dnl IBM XL C    -qlanglvl=extended0x
 817 dnl             (pre-V12.1; unused restrictive mode: -qlanglvl=stdcxx11)
 818 dnl HP aC++     -AA
 819 dnl Intel ICC   -std=c++11 -std=c++0x
 820 dnl Solaris     N/A (no support)
 821 dnl Tru64       N/A (no support)
 822 dnl with extended modes being tried first.
 823 [[-std=gnu++11 -std=c++11 -std=gnu++0x -std=c++0x -qlanglvl=extended0x -AA]], [$1], [$2])[]dnl
 824 ])# _AC_PROG_CXX_CXX11